diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index aeb98a89233..92e87e03594 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -1,25 +1,7 @@
 name: Builds, tests & co
 
 on:
-  pull_request:
-    paths:
-      - 'src/**'
-      - '!src/tools/**'
-      - 'src_ext/**'
-      - 'dune'
-      - 'dune-project'
-      - '*.opam'
-      - 'Makefile*'
-      - 'configure*'
-      - '.github/scripts/**'
-      - '.github/workflows/main.yml'
-      - 'tests/**'
-      - '!tests/bench/**'
-      - 'shell/'
   push:
-    branches:
-      - 'master'
-      - '2.**'
 
 env:
   OPAMBSVERSION: 2.1.0
@@ -78,26 +60,6 @@ jobs:
       if: steps.archives.outputs.cache-hit != 'true'
       run: bash -exu .github/scripts/main/archives-cache.sh
 
-  Cygwin:
-    runs-on: windows-2019
-    needs: Analyse
-    steps:
-    - name: Cygwin64 Cache
-      id: cygwin64
-      uses: actions/cache@v4
-      with:
-        path: D:\Cache\cygwin\x86_64-pc-cygwin
-        key: cygwin64-${{ needs.Analyse.outputs.cygwin }}
-        lookup-only: true
-        enableCrossOsArchive: true
-    - name: Checkout tree
-      if: steps.cygwin64.outputs.cache-hit != 'true'
-      uses: actions/checkout@v4
-    - name: Create Cygwin64 cache
-      if: steps.cygwin64.outputs.cache-hit != 'true'
-      shell: cmd
-      run: .github\scripts\cygwin.cmd x86_64-pc-cygwin D:\Cache\cygwin create
-
 ####
 # Build
 ####
@@ -136,264 +98,6 @@ jobs:
     - name: Test (basic)
       run: bash -exu .github/scripts/main/test.sh
 
-  Build-Windows:
-    runs-on: windows-2019
-    needs: [ Analyse, Cygwin ]
-    strategy:
-      matrix:
-        host: [ x86_64-pc-cygwin, i686-w64-mingw32, x86_64-w64-mingw32, i686-pc-windows, x86_64-pc-windows ]
-        build: [ x86_64-pc-cygwin ]
-        ocamlv: [ 4.14.1 ]
-      fail-fast: false
-    defaults:
-      run:
-        shell: D:\cygwin\bin\bash.exe {0}
-    steps:
-    - name: Configure LF checkout for Cygwin
-      if: endsWith(matrix.host, '-pc-cygwin')
-      shell: cmd
-      run: |
-        git config --system core.autocrlf false
-        git config --system core.eol lf
-    - name: Checkout tree
-      uses: actions/checkout@v4
-    - name: Cygwin64 Cache
-      id: cygwin64
-      if: matrix.build == 'x86_64-pc-cygwin'
-      uses: actions/cache@v4
-      with:
-        path: D:\Cache\cygwin\x86_64-pc-cygwin
-        key: cygwin64-${{ needs.Analyse.outputs.cygwin }}
-        enableCrossOsArchive: true
-    - name: src_ext/archives and opam-repository Cache
-      id: archives
-      uses: actions/cache@v4
-      with:
-        path: |
-          src_ext/archives
-          ~/opam-repository
-        key: ${{ needs.Analyse.outputs.archives }}
-        enableCrossOsArchive: true
-    - name: OCaml ${{ matrix.ocamlv }} Cache
-      id: ocaml-cache
-      uses: actions/cache@v4
-      with:
-        path: D:\Cache\ocaml-local.tar
-        key: ${{ runner.os }}-${{ matrix.host }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
-        enableCrossOsArchive: true
-    - name: Unpack Cygwin
-      shell: cmd
-      run: .github\scripts\cygwin.cmd ${{ matrix.build }} D:\Cache\cygwin ${{ matrix.host }}
-    - name: Unpack OCaml ${{ matrix.ocamlv }}
-      run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }} ${{ matrix.host }}
-    - name: Build
-      run: bash -exu .github/scripts/main/main.sh ${{ matrix.host }}
-    - name: Test "static" binaries on Windows
-      if: endsWith(matrix.host, '-pc-cygwin') == false
-      run: ldd ./opam.exe | test "$(grep -v -F /cygdrive/c/Windows/)" = ''
-    - name: Upload opam binaries for Windows
-      if: endsWith(matrix.host, '-pc-windows')
-      uses: actions/upload-artifact@v4
-      with:
-        name: opam-exe-${{ matrix.host }}-${{ matrix.ocamlv }}-${{ matrix.build }}
-        path: |
-          D:\Local\bin\opam.exe
-          D:\Local\bin\opam-installer.exe
-          D:\Local\bin\opam-putenv.exe
-    - name: Test (basic - Cygwin)
-      if: endsWith(matrix.host, '-pc-cygwin')
-      run: bash -exu .github/scripts/main/test.sh
-    - name: Test (basic - native Windows)
-      env:
-        OPAMROOT: D:\a\opam\opam\.opam
-      if: endsWith(matrix.host, '-pc-cygwin') == false
-      shell: cmd
-      run: |
-        set Path=D:\Cache\ocaml-local\bin;%Path%
-        if "${{ matrix.host }}" equ "x86_64-pc-windows" call "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
-        if "${{ matrix.host }}" equ "i686-pc-windows" call "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvars32.bat"
-        opam init --yes --bare default git+file://D:/opam-repository#${{ env.OPAM_TEST_REPO_SHA }} --no-git-location || exit /b 1
-        opam switch --yes create default ocaml-system || exit /b 1
-        opam env || exit /b 1
-        opam install --yes lwt || exit /b 1
-        opam list || exit /b 1
-        opam config report || exit /b 1
-    - name: Test (reftests)
-      run: bash -exu .github/scripts/main/reftests.sh ${{ matrix.host }}
-
-  Build-macOS:
-    runs-on: macos-latest
-    needs: Analyse
-    strategy:
-      matrix:
-        ocamlv: [ 4.14.1 ]
-      fail-fast: true
-    steps:
-    - name: Checkout tree
-      uses: actions/checkout@v4
-    - name: src_ext/archives and opam-repository Cache
-      id: archives
-      uses: actions/cache@v4
-      with:
-        path: |
-          src_ext/archives
-          ~/opam-repository
-        key: ${{ needs.Analyse.outputs.archives }}
-        enableCrossOsArchive: true
-    - name: OCaml ${{ matrix.ocamlv }} Cache
-      id: ocaml-cache
-      uses: actions/cache@v4
-      with:
-        path: ~/.cache/ocaml-local/**
-        key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
-    - name: Create OCaml ${{ matrix.ocamlv }} cache
-      if: steps.ocaml-cache.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
-    - name: Build
-      run: bash -exu .github/scripts/main/main.sh x86_64-apple-darwin
-    - name: Test (basic)
-      run: bash -exu .github/scripts/main/test.sh
-
-####
-# Opam tests
-####
-  Test-Linux:
-    runs-on: ubuntu-latest
-    needs: [ Analyse, Build-Linux ]
-    strategy:
-      matrix:
-        ocamlv: [ 4.14.1 ]
-      fail-fast: false
-    env:
-      OPAM_TEST: 1
-    steps:
-    - name: Checkout tree
-      uses: actions/checkout@v4
-    - name: Install bubblewrap
-      run: sudo apt install bubblewrap
-    - name: src_ext/archives and opam-repository Cache
-      id: archives
-      uses: actions/cache@v4
-      with:
-        path: |
-          src_ext/archives
-          ~/opam-repository
-        key: ${{ needs.Analyse.outputs.archives }}
-        enableCrossOsArchive: true
-    - name: OCaml ${{ matrix.ocamlv }} Cache
-      id: ocaml-cache
-      uses: actions/cache@v4
-      with:
-        path: ~/.cache/ocaml-local/**
-        key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
-    - name: Create OCaml ${{ matrix.ocamlv }} cache
-      if: steps.ocaml-cache.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
-    - name: opam bootstrap Cache
-      id: opam-bootstrap
-      uses: actions/cache@v4
-      with:
-        path: |
-          ${{ env.OPAMBSROOT }}/**
-          ~/.cache/opam-local/bin/**
-        key: opam-${{ runner.os }}-${{ env.OPAMBSVERSION }}-${{ matrix.ocamlv }}-${{ env.OPAM_REPO_SHA }}-${{ needs.Analyse.outputs.opam-bs-cache }}
-    - name: Create opam bootstrap cache
-      if: steps.opam-bootstrap.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/opam-bs-cache.sh
-    - name: opam-rt Cache
-      id: opam-rt
-      uses: actions/cache@v4
-      with:
-        path: ~/.cache/opam-rt/**
-        key: ${{ runner.os }}-opam-rt-${{ matrix.ocamlv }}
-    - name: Build (and test)
-      run: bash -exu .github/scripts/main/main.sh x86_64-pc-linux-gnu
-    - name: Test (opam-rt)
-      run: bash -exu .github/scripts/main/opam-rt.sh
-
-  Test-macOS:
-    runs-on: macos-latest
-    needs: Analyse
-    strategy:
-      matrix:
-        ocamlv: [ 4.14.1 ]
-      fail-fast: false
-    env:
-      OPAM_TEST: 1
-    steps:
-    - name: Install gnu coreutils
-      run: brew install coreutils gpatch
-    - name: Checkout tree
-      uses: actions/checkout@v4
-    - name: src_ext/archives and opam-repository Cache
-      id: archives
-      uses: actions/cache@v4
-      with:
-        path: |
-          src_ext/archives
-          ~/opam-repository
-        key: ${{ needs.Analyse.outputs.archives }}
-        enableCrossOsArchive: true
-    - name: OCaml ${{ matrix.ocamlv }} Cache
-      id: ocaml-cache
-      uses: actions/cache@v4
-      with:
-        path: ~/.cache/ocaml-local/**
-        key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
-    - name: Create OCaml ${{ matrix.ocamlv }} cache
-      if: steps.ocaml-cache.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
-    - name: opam bootstrap Cache
-      id: opam-bootstrap
-      uses: actions/cache@v4
-      with:
-        path: |
-          ${{ env.OPAMBSROOT }}/**
-          ~/.cache/opam-local/bin/**
-        key: opam-${{ runner.os }}-${{ env.OPAMBSVERSION }}-${{ matrix.ocamlv }}-${{ env.OPAM_REPO_SHA }}-${{ needs.Analyse.outputs.opam-bs-cache }}
-    - name: Create opam bootstrap cache
-      if: steps.opam-bootstrap.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/opam-bs-cache.sh
-    - name: opam-rt Cache
-      id: opam-rt
-      uses: actions/cache@v4
-      with:
-        path: ~/.cache/opam-rt/**
-        key: ${{ runner.os }}-opam-rt-${{ matrix.ocamlv }}
-    - name: Build (and test)
-      run: bash -exu .github/scripts/main/main.sh x86_64-apple-darwin
-    - name: Test (opam-rt)
-      run: bash -exu .github/scripts/main/opam-rt.sh
-
-####
-# Opam cold
-####
-  Cold-Linux:
-    runs-on: ubuntu-latest
-    needs: [ Analyse, Build-Linux ]
-    env:
-      OPAM_COLD: 1
-    steps:
-    - name: Install bubblewrap
-      run: sudo apt install bubblewrap
-    - name: Checkout tree
-      uses: actions/checkout@v4
-    - name: src_ext/archives and opam-repository Cache
-      id: archives
-      uses: actions/cache@v4
-      with:
-        path: |
-          src_ext/archives
-          ~/opam-repository
-        key: ${{ needs.Analyse.outputs.archives }}
-        enableCrossOsArchive: true
-    - name: Cold
-      run: |
-        make compiler
-        bash -exu .github/scripts/main/main.sh x86_64-pc-linux-gnu
-    - name: Test (basic)
-      run: bash -exu .github/scripts/main/test.sh
-
 ####
 # Compile doc
 ####
@@ -447,211 +151,3 @@ jobs:
         BASE_REF_SHA: ${{ github.event.pull_request.base.sha }}
         PR_REF_SHA: ${{ github.event.pull_request.head.sha }}
       run: bash -exu .github/scripts/main/main.sh x86_64-pc-linux-gnu
-
-####
-# Compile solver backends
-####
-  Solvers-Linux:
-    runs-on: ubuntu-latest
-    needs: [ Analyse, Build-Linux ]
-    strategy:
-      matrix:
-        solver: [ z3, 0install ]
-        ocamlv: [ 4.14.1 ]
-      fail-fast: false
-    env:
-      SOLVER: ${{ matrix.solver }}
-      OPAMBSROOT: ~/.cache/opam.${{ matrix.solver }}.cached
-    steps:
-    - name: Install bubblewrap
-      run: sudo apt install bubblewrap
-    - name: Checkout tree
-      uses: actions/checkout@v4
-    - name: src_ext/archives and opam-repository Cache
-      id: archives
-      uses: actions/cache@v4
-      with:
-        path: |
-          src_ext/archives
-          ~/opam-repository
-        key: ${{ needs.Analyse.outputs.archives }}
-        enableCrossOsArchive: true
-    - name: OCaml ${{ matrix.ocamlv }} Cache
-      id: ocaml-cache
-      uses: actions/cache@v4
-      with:
-        path: ~/.cache/ocaml-local/**
-        key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
-    - name: Create OCaml ${{ matrix.ocamlv }} cache
-      if: steps.ocaml-cache.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
-    - name: opam bootstrap Cache
-      id: opam-bootstrap
-      uses: actions/cache@v4
-      with:
-        path: |
-          ${{ env.OPAMBSROOT }}/**
-          ~/.cache/opam-local/bin/**
-        key: opam-${{ matrix.solver }}-${{ runner.os }}-${{ env.OPAMBSVERSION }}-${{ matrix.ocamlv }}-${{ env.OPAM_REPO_SHA }}-${{ needs.Analyse.outputs.opam-bs-cache }}
-    - name: Create opam bootstrap cache
-      if: steps.opam-bootstrap.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/opam-bs-cache.sh
-    - name: Compile
-      run: bash -exu .github/scripts/main/solvers.sh
-
-  Solvers-macOS:
-    runs-on: macos-latest
-    needs: [ Analyse, Build-macOS ]
-    strategy:
-      matrix:
-        solver: [ z3, 0install ]
-        ocamlv: [ 4.14.1 ]
-      fail-fast: false
-    env:
-      SOLVER: ${{ matrix.solver }}
-      OPAMBSROOT: ~/.cache/opam.${{ matrix.solver }}.cached
-    steps:
-    - name: Checkout tree
-      uses: actions/checkout@v4
-    - name: src_ext/archives and opam-repository Cache
-      id: archives
-      uses: actions/cache@v4
-      with:
-        path: |
-          src_ext/archives
-          ~/opam-repository
-        key: ${{ needs.Analyse.outputs.archives }}
-        enableCrossOsArchive: true
-    - name: OCaml ${{ matrix.ocamlv }} Cache
-      id: ocaml-cache
-      uses: actions/cache@v4
-      with:
-        path: ~/.cache/ocaml-local/**
-        key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
-    - name: Create OCaml ${{ matrix.ocamlv }} cache
-      if: steps.ocaml-cache.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
-    - name: opam bootstrap Cache
-      id: opam-bootstrap
-      uses: actions/cache@v4
-      with:
-        path: |
-          ${{ env.OPAMBSROOT }}/**
-          ~/.cache/opam-local/bin/**
-        key: opam-${{ matrix.solver }}-${{ runner.os }}-${{ env.OPAMBSVERSION }}-${{ matrix.ocamlv }}-${{ env.OPAM_REPO_SHA }}-${{ needs.Analyse.outputs.opam-bs-cache }}
-    - name: Create opam bootstrap cache
-      if: steps.opam-bootstrap.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/opam-bs-cache.sh
-    - name: Compile
-      run: bash -exu .github/scripts/main/solvers.sh
-
-####
-# Upgrade from 1.2 to current
-####
-  Upgrade-Linux:
-    runs-on: ubuntu-latest
-    needs: [ Analyse, Build-Linux ]
-    strategy:
-      matrix:
-        ocamlv: [ 4.14.1 ]
-      fail-fast: false
-    steps:
-    - name: Install bubblewrap
-      run: sudo apt install bubblewrap
-    - name: Checkout tree
-      uses: actions/checkout@v4
-    - name: opam 1.2 root Cache
-      uses: actions/cache@v4
-      with:
-        path: ${{ env.OPAM12CACHE }}
-        key: ${{ runner.os }}-opam1.2-root
-    - name: OCaml ${{ matrix.ocamlv }} Cache
-      id: ocaml-cache
-      uses: actions/cache@v4
-      with:
-        path: ~/.cache/ocaml-local/**
-        key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
-    - name: Create OCaml ${{ matrix.ocamlv }} cache
-      if: steps.ocaml-cache.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
-    - name: Build
-      env:
-        OPAM_UPGRADE: 1
-      run: bash -exu .github/scripts/main/main.sh x86_64-pc-linux-gnu
-    - name: Test (upgrade)
-      run: bash -exu .github/scripts/main/upgrade.sh
-
-  Upgrade-macOS:
-    runs-on: macos-latest
-    needs: [ Analyse, Build-macOS ]
-    strategy:
-      matrix:
-        ocamlv: [ 4.14.1 ]
-      fail-fast: false
-    steps:
-    - name: Checkout tree
-      uses: actions/checkout@v4
-    - name: opam 1.2 root Cache
-      uses: actions/cache@v4
-      with:
-        path: ${{ env.OPAM12CACHE }}
-        key: ${{ runner.os }}-opam1.2-root
-    - name: OCaml ${{ matrix.ocamlv }} Cache
-      id: ocaml-cache
-      uses: actions/cache@v4
-      with:
-        path: ~/.cache/ocaml-local/**
-        key: ${{ runner.os }}-ocaml-${{ matrix.ocamlv }}-${{ needs.Analyse.outputs.ocaml-cache }}
-    - name: Create OCaml ${{ matrix.ocamlv }} cache
-      if: steps.ocaml-cache.outputs.cache-hit != 'true'
-      run: bash -exu .github/scripts/main/ocaml-cache.sh ${{ runner.os }} ${{ matrix.ocamlv }}
-    - name: Build
-      env:
-        OPAM_UPGRADE: 1
-      run: bash -exu .github/scripts/main/main.sh x86_64-apple-darwin
-    - name: Test (upgrade)
-      run: bash -exu .github/scripts/main/upgrade.sh
-
-####
-# Around opam tests
-####
-  Hygiene:
-    runs-on: ubuntu-22.04
-    needs: Analyse
-    steps:
-    - name: Install system's dune and ocaml packages
-      run: sudo apt install dune ocaml
-    - name: Checkout tree
-      uses: actions/checkout@v4
-    - name: src_ext/archives and opam-repository Cache
-      id: archives
-      uses: actions/cache@v4
-      with:
-        path: |
-          src_ext/archives
-          ~/opam-repository
-        key: ${{ needs.Analyse.outputs.archives }}
-        enableCrossOsArchive: true
-    - name: Get changed files
-      id: files
-      uses: Ana06/get-changed-files@v2.2.0
-    - name: Changed files list
-      run: |
-        for changed_file in ${{ steps.files.outputs.modified }}; do
-          echo "M  ${changed_file}."
-        done
-        for changed_file in ${{ steps.files.outputs.removed }}; do
-          echo "D  ${changed_file}."
-        done
-        for changed_file in ${{ steps.files.outputs.added }}; do
-          echo "A  ${changed_file}."
-        done
-        for changed_file in ${{ steps.files.outputs.renamed }}; do
-          echo "AD ${changed_file}."
-        done
-    - name: Hygiene
-      env:
-        BASE_REF_SHA: ${{ github.event.pull_request.base.sha }}
-        PR_REF_SHA: ${{ github.event.pull_request.head.sha }}
-      if: contains(steps.files.outputs.modified, 'configure.ac') || contains(steps.files.outputs.all, 'src_ext') || contains(steps.files.outputs.all, '.github/workflows')
-      run: bash -exu .github/scripts/main/hygiene.sh